- merge events branch, [ticket:1902]

1 files changed, 74 insertions, 713 deletions

diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index aefccb63a..6872dd645 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -3,24 +3,20 @@
 #
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
-"""Defines SQLAlchemy's system of class instrumentation..
+"""Defines instrumentation for class attributes and their interaction
+with instances.
 
 This module is usually not directly visible to user applications, but
 defines a large part of the ORM's interactivity.
 
-SQLA's instrumentation system is completely customizable, in which
-case an understanding of the general mechanics of this module is helpful.
-An example of full customization is in /examples/custom_attributes.
 
 """
 
 import operator
-from operator import attrgetter, itemgetter
-import types
-import weakref
+from operator import itemgetter
 
-from sqlalchemy import util
-from sqlalchemy.orm import interfaces, collections, exc
+from sqlalchemy import util, event
+from sqlalchemy.orm import interfaces, collections, events
 import sqlalchemy.exceptions as sa_exc
 
 mapperutil = util.importlater("sqlalchemy.orm", "util")
@@ -52,62 +48,30 @@ Loads of "previous" values during change events use this flag.
 PASSIVE_OFF = False #util.symbol('PASSIVE_OFF')
 """Symbol indicating that loader callables should be executed."""
 
-INSTRUMENTATION_MANAGER = '__sa_instrumentation_manager__'
-"""Attribute, elects custom instrumentation when present on a mapped class.
-
-Allows a class to specify a slightly or wildly different technique for
-tracking changes made to mapped attributes and collections.
-
-Only one instrumentation implementation is allowed in a given object
-inheritance hierarchy.
-
-The value of this attribute must be a callable and will be passed a class
-object.  The callable must return one of:
-
-  - An instance of an interfaces.InstrumentationManager or subclass
-  - An object implementing all or some of InstrumentationManager (TODO)
-  - A dictionary of callables, implementing all or some of the above (TODO)
-  - An instance of a ClassManager or subclass
-
-interfaces.InstrumentationManager is public API and will remain stable
-between releases.  ClassManager is not public and no guarantees are made
-about stability.  Caveat emptor.
-
-This attribute is consulted by the default SQLAlchemy instrumentation
-resolution code.  If custom finders are installed in the global
-instrumentation_finders list, they may or may not choose to honor this
-attribute.
-
-"""
-
-instrumentation_finders = []
-"""An extensible sequence of instrumentation implementation finding callables.
-
-Finders callables will be passed a class object.  If None is returned, the
-next finder in the sequence is consulted.  Otherwise the return must be an
-instrumentation factory that follows the same guidelines as
-INSTRUMENTATION_MANAGER.
-
-By default, the only finder is find_native_user_instrumentation_hook, which
-searches for INSTRUMENTATION_MANAGER.  If all finders return None, standard
-ClassManager instrumentation is used.
-
-"""
 
 class QueryableAttribute(interfaces.PropComparator):
-
-    def __init__(self, key, impl=None, comparator=None, parententity=None):
-        """Construct an InstrumentedAttribute.
-
-          comparator
-            a sql.Comparator to which class-level compare/math events will be
-            sent
-        """
+    """Base class for class-bound attributes. """
+    
+    def __init__(self, class_, key, impl=None, 
+                        comparator=None, parententity=None):
+        self.class_ = class_
         self.key = key
         self.impl = impl
         self.comparator = comparator
         self.parententity = parententity
-
+        
+        manager = manager_of_class(class_)
+        # manager is None in the case of AliasedClass
+        if manager:
+            # propagate existing event listeners from 
+            # immediate superclass
+            for base in manager._bases:
+                if key in base:
+                    self.dispatch.update(base[key].dispatch)
+
+    dispatch = event.dispatcher(events.AttributeEvents)
+    dispatch.dispatch_cls.active_history = False
+    
     def get_history(self, instance, **kwargs):
         return self.impl.get_history(instance_state(instance),
                                         instance_dict(instance), **kwargs)
@@ -151,7 +115,7 @@ class QueryableAttribute(interfaces.PropComparator):
 
 
 class InstrumentedAttribute(QueryableAttribute):
-    """Public-facing descriptor, placed in the mapped class dictionary."""
+    """Class bound instrumented attribute which adds descriptor methods."""
 
     def __set__(self, instance, value):
         self.impl.set(instance_state(instance), 
@@ -240,7 +204,7 @@ class AttributeImpl(object):
     """internal implementation for instrumented attributes."""
 
     def __init__(self, class_, key,
-                    callable_, trackparent=False, extension=None,
+                    callable_, dispatch, trackparent=False, extension=None,
                     compare_function=None, active_history=False, 
                     parent_token=None, expire_missing=True,
                     **kwargs):
@@ -264,7 +228,8 @@ class AttributeImpl(object):
 
         extension
           a single or list of AttributeExtension object(s) which will
-          receive set/delete/append/remove/etc. events.
+          receive set/delete/append/remove/etc. events.  Deprecated.
+          The event package is now used.
 
         compare_function
           a function that compares two values which are normally
@@ -289,18 +254,24 @@ class AttributeImpl(object):
         self.class_ = class_
         self.key = key
         self.callable_ = callable_
+        self.dispatch = dispatch
         self.trackparent = trackparent
         self.parent_token = parent_token or self
         if compare_function is None:
             self.is_equal = operator.eq
         else:
             self.is_equal = compare_function
-        self.extensions = util.to_list(extension or [])
-        for e in self.extensions:
-            if e.active_history:
-                active_history = True
-                break
-        self.active_history = active_history
+        
+        # TODO: pass in the manager here
+        # instead of doing a lookup
+        attr = manager_of_class(class_)[key]
+        
+        for ext in util.to_list(extension or []):
+            ext._adapt_listener(attr, ext)
+            
+        if active_history:
+            self.dispatch.active_history = True
+
         self.expire_missing = expire_missing
         
         
@@ -437,12 +408,12 @@ class ScalarAttributeImpl(AttributeImpl):
     def delete(self, state, dict_):
 
         # TODO: catch key errors, convert to attributeerror?
-        if self.active_history:
+        if self.dispatch.active_history:
             old = self.get(state, dict_)
         else:
             old = dict_.get(self.key, NO_VALUE)
 
-        if self.extensions:
+        if self.dispatch.on_remove:
             self.fire_remove_event(state, dict_, old, None)
         state.modified_event(dict_, self, False, old)
         del dict_[self.key]
@@ -455,25 +426,25 @@ class ScalarAttributeImpl(AttributeImpl):
         if initiator and initiator.parent_token is self.parent_token:
             return
 
-        if self.active_history:
+        if self.dispatch.active_history:
             old = self.get(state, dict_)
         else:
             old = dict_.get(self.key, NO_VALUE)
 
-        if self.extensions:
+        if self.dispatch.on_set:
             value = self.fire_replace_event(state, dict_, 
                                                 value, old, initiator)
         state.modified_event(dict_, self, False, old)
         dict_[self.key] = value
 
     def fire_replace_event(self, state, dict_, value, previous, initiator):
-        for ext in self.extensions:
-            value = ext.set(state, value, previous, initiator or self)
+        for fn in self.dispatch.on_set:
+            value = fn(state, value, previous, initiator or self)
         return value
 
     def fire_remove_event(self, state, dict_, value, initiator):
-        for ext in self.extensions:
-            ext.remove(state, value, initiator or self)
+        for fn in self.dispatch.on_remove:
+            fn(state, value, initiator or self)
 
     @property
     def type(self):
@@ -489,13 +460,13 @@ class MutableScalarAttributeImpl(ScalarAttributeImpl):
     uses_objects = False
     supports_population = True
 
-    def __init__(self, class_, key, callable_,
+    def __init__(self, class_, key, callable_, dispatch,
                     class_manager, copy_function=None,
                     compare_function=None, **kwargs):
         super(ScalarAttributeImpl, self).__init__(
                                             class_, 
                                             key, 
-                                            callable_,
+                                            callable_, dispatch,
                                             compare_function=compare_function, 
                                             **kwargs)
         class_manager.mutable_attributes.add(key)
@@ -534,7 +505,7 @@ class MutableScalarAttributeImpl(ScalarAttributeImpl):
         if initiator and initiator.parent_token is self.parent_token:
             return
 
-        if self.extensions:
+        if self.dispatch.on_set:
             old = self.get(state, dict_)
             value = self.fire_replace_event(state, dict_, 
                                             value, old, initiator)
@@ -556,13 +527,13 @@ class ScalarObjectAttributeImpl(ScalarAttributeImpl):
     uses_objects = True
     supports_population = True
 
-    def __init__(self, class_, key, callable_, 
+    def __init__(self, class_, key, callable_, dispatch,
                     trackparent=False, extension=None, copy_function=None,
                     compare_function=None, **kwargs):
         super(ScalarObjectAttributeImpl, self).__init__(
                                             class_, 
                                             key,
-                                            callable_, 
+                                            callable_, dispatch, 
                                             trackparent=trackparent, 
                                             extension=extension,
                                             compare_function=compare_function, 
@@ -596,7 +567,7 @@ class ScalarObjectAttributeImpl(ScalarAttributeImpl):
         if initiator and initiator.parent_token is self.parent_token:
             return
 
-        if self.active_history:
+        if self.dispatch.active_history:
             old = self.get(state, dict_, passive=PASSIVE_ONLY_PERSISTENT)
         else:
             old = self.get(state, dict_, passive=PASSIVE_NO_FETCH)
@@ -607,9 +578,9 @@ class ScalarObjectAttributeImpl(ScalarAttributeImpl):
     def fire_remove_event(self, state, dict_, value, initiator):
         if self.trackparent and value is not None:
             self.sethasparent(instance_state(value), False)
-
-        for ext in self.extensions:
-            ext.remove(state, value, initiator or self)
+        
+        for fn in self.dispatch.on_remove:
+            fn(state, value, initiator or self)
 
         state.modified_event(dict_, self, False, value)
 
@@ -620,8 +591,8 @@ class ScalarObjectAttributeImpl(ScalarAttributeImpl):
                 previous is not PASSIVE_NO_RESULT):
                 self.sethasparent(instance_state(previous), False)
         
-        for ext in self.extensions:
-            value = ext.set(state, value, previous, initiator or self)
+        for fn in self.dispatch.on_set:
+            value = fn(state, value, previous, initiator or self)
 
         state.modified_event(dict_, self, False, previous)
 
@@ -647,13 +618,13 @@ class CollectionAttributeImpl(AttributeImpl):
     uses_objects = True
     supports_population = True
 
-    def __init__(self, class_, key, callable_, 
+    def __init__(self, class_, key, callable_, dispatch,
                     typecallable=None, trackparent=False, extension=None,
                     copy_function=None, compare_function=None, **kwargs):
         super(CollectionAttributeImpl, self).__init__(
                                             class_, 
                                             key, 
-                                            callable_, 
+                                            callable_, dispatch,
                                             trackparent=trackparent,
                                             extension=extension,
                                             compare_function=compare_function, 
@@ -675,8 +646,8 @@ class CollectionAttributeImpl(AttributeImpl):
             return History.from_attribute(self, state, current)
 
     def fire_append_event(self, state, dict_, value, initiator):
-        for ext in self.extensions:
-            value = ext.append(state, value, initiator or self)
+        for fn in self.dispatch.on_append:
+            value = fn(state, value, initiator or self)
 
         state.modified_event(dict_, self, True, 
                                 NEVER_SET, passive=PASSIVE_NO_INITIALIZE)
@@ -694,8 +665,8 @@ class CollectionAttributeImpl(AttributeImpl):
         if self.trackparent and value is not None:
             self.sethasparent(instance_state(value), False)
 
-        for ext in self.extensions:
-            ext.remove(state, value, initiator or self)
+        for fn in self.dispatch.on_remove:
+            fn(state, value, initiator or self)
 
         state.modified_event(dict_, self, True, 
                                 NEVER_SET, passive=PASSIVE_NO_INITIALIZE)
@@ -909,394 +880,6 @@ class GenericBackrefExtension(interfaces.AttributeExtension):
                                             passive=PASSIVE_NO_FETCH)
 
 
-class Events(object):
-    def __init__(self):
-        self.original_init = object.__init__
-        # Initialize to tuples instead of lists to minimize the memory 
-        # footprint
-        self.on_init = ()
-        self.on_init_failure = ()
-        self.on_load = ()
-        self.on_resurrect = ()
-
-    def run(self, event, *args):
-        for fn in getattr(self, event):
-            fn(*args)
-
-    def add_listener(self, event, listener):
-        # not thread safe... problem?  mb: nope
-        bucket = getattr(self, event)
-        if bucket == ():
-            setattr(self, event, [listener])
-        else:
-            bucket.append(listener)
-
-    def remove_listener(self, event, listener):
-        bucket = getattr(self, event)
-        bucket.remove(listener)
-
-
-class ClassManager(dict):
-    """tracks state information at the class level."""
-
-    MANAGER_ATTR = '_sa_class_manager'
-    STATE_ATTR = '_sa_instance_state'
-
-    event_registry_factory = Events
-    deferred_scalar_loader = None
-    
-    def __init__(self, class_):
-        self.class_ = class_
-        self.factory = None  # where we came from, for inheritance bookkeeping
-        self.info = {}
-        self.new_init = None
-        self.mutable_attributes = set()
-        self.local_attrs = {}
-        self.originals = {}
-        for base in class_.__mro__[-2:0:-1]:  # reverse, skipping 1st and last
-            if not isinstance(base, type):
-                continue
-            cls_state = manager_of_class(base)
-            if cls_state:
-                self.update(cls_state)
-        self.events = self.event_registry_factory()
-        self.manage()
-        self._instrument_init()
-    
-    @property
-    def is_mapped(self):
-        return 'mapper' in self.__dict__
-        
-    @util.memoized_property
-    def mapper(self):
-        raise exc.UnmappedClassError(self.class_)
-        
-    def _attr_has_impl(self, key):
-        """Return True if the given attribute is fully initialized.
-        
-        i.e. has an impl.
-        """
-        
-        return key in self and self[key].impl is not None
-        
-    def _configure_create_arguments(self, 
-                            _source=None, 
-                            deferred_scalar_loader=None):
-        """Accept extra **kw arguments passed to create_manager_for_cls.
-        
-        The current contract of ClassManager and other managers is that they
-        take a single "cls" argument in their constructor (as per 
-        test/orm/instrumentation.py InstrumentationCollisionTest).  This
-        is to provide consistency with the current API of "class manager"
-        callables and such which may return various ClassManager and 
-        ClassManager-like instances.   So create_manager_for_cls sends
-        in ClassManager-specific arguments via this method once the 
-        non-proxied ClassManager is available.
-        
-        """
-        if _source:
-            deferred_scalar_loader = _source.deferred_scalar_loader
-
-        if deferred_scalar_loader:
-            self.deferred_scalar_loader = deferred_scalar_loader
-    
-    def _subclass_manager(self, cls):
-        """Create a new ClassManager for a subclass of this ClassManager's
-        class.
-        
-        This is called automatically when attributes are instrumented so that
-        the attributes can be propagated to subclasses against their own
-        class-local manager, without the need for mappers etc. to have already
-        pre-configured managers for the full class hierarchy.   Mappers
-        can post-configure the auto-generated ClassManager when needed.
-        
-        """
-        manager = manager_of_class(cls)
-        if manager is None:
-            manager = _create_manager_for_cls(cls, _source=self)
-        return manager
-        
-    def _instrument_init(self):
-        # TODO: self.class_.__init__ is often the already-instrumented
-        # __init__ from an instrumented superclass.  We still need to make 
-        # our own wrapper, but it would
-        # be nice to wrap the original __init__ and not our existing wrapper
-        # of such, since this adds method overhead.
-        self.events.original_init = self.class_.__init__
-        self.new_init = _generate_init(self.class_, self)
-        self.install_member('__init__', self.new_init)
-        
-    def _uninstrument_init(self):
-        if self.new_init:
-            self.uninstall_member('__init__')
-            self.new_init = None
-    
-    def _create_instance_state(self, instance):
-        if self.mutable_attributes:
-            return state.MutableAttrInstanceState(instance, self)
-        else:
-            return state.InstanceState(instance, self)
-        
-    def manage(self):
-        """Mark this instance as the manager for its class."""
-        
-        setattr(self.class_, self.MANAGER_ATTR, self)
-
-    def dispose(self):
-        """Dissasociate this manager from its class."""
-        
-        delattr(self.class_, self.MANAGER_ATTR)
-
-    def manager_getter(self):
-        return attrgetter(self.MANAGER_ATTR)
-
-    def instrument_attribute(self, key, inst, propagated=False):
-        if propagated:
-            if key in self.local_attrs:
-                return  # don't override local attr with inherited attr
-        else:
-            self.local_attrs[key] = inst
-            self.install_descriptor(key, inst)
-        self[key] = inst
-        
-        for cls in self.class_.__subclasses__():
-            manager = self._subclass_manager(cls)
-            manager.instrument_attribute(key, inst, True)
-
-    def post_configure_attribute(self, key):
-        pass
-        
-    def uninstrument_attribute(self, key, propagated=False):
-        if key not in self:
-            return
-        if propagated:
-            if key in self.local_attrs:
-                return  # don't get rid of local attr
-        else:
-            del self.local_attrs[key]
-            self.uninstall_descriptor(key)
-        del self[key]
-        if key in self.mutable_attributes:
-            self.mutable_attributes.remove(key)
-        for cls in self.class_.__subclasses__():
-            manager = self._subclass_manager(cls)
-            manager.uninstrument_attribute(key, True)
-
-    def unregister(self):
-        """remove all instrumentation established by this ClassManager."""
-        
-        self._uninstrument_init()
-
-        self.mapper = self.events = None
-        self.info.clear()
-        
-        for key in list(self):
-            if key in self.local_attrs:
-                self.uninstrument_attribute(key)
-
-    def install_descriptor(self, key, inst):
-        if key in (self.STATE_ATTR, self.MANAGER_ATTR):
-            raise KeyError("%r: requested attribute name conflicts with "
-                           "instrumentation attribute of the same name." %
-                           key)
-        setattr(self.class_, key, inst)
-
-    def uninstall_descriptor(self, key):
-        delattr(self.class_, key)
-
-    def install_member(self, key, implementation):
-        if key in (self.STATE_ATTR, self.MANAGER_ATTR):
-            raise KeyError("%r: requested attribute name conflicts with "
-                           "instrumentation attribute of the same name." %
-                           key)
-        self.originals.setdefault(key, getattr(self.class_, key, None))
-        setattr(self.class_, key, implementation)
-
-    def uninstall_member(self, key):
-        original = self.originals.pop(key, None)
-        if original is not None:
-            setattr(self.class_, key, original)
-
-    def instrument_collection_class(self, key, collection_class):
-        return collections.prepare_instrumentation(collection_class)
-
-    def initialize_collection(self, key, state, factory):
-        user_data = factory()
-        adapter = collections.CollectionAdapter(
-            self.get_impl(key), state, user_data)
-        return adapter, user_data
-
-    def is_instrumented(self, key, search=False):
-        if search:
-            return key in self
-        else:
-            return key in self.local_attrs
-
-    def get_impl(self, key):
-        return self[key].impl
-
-    @property
-    def attributes(self):
-        return self.itervalues()
-
-    ## InstanceState management
-
-    def new_instance(self, state=None):
-        instance = self.class_.__new__(self.class_)
-        setattr(instance, self.STATE_ATTR, 
-                    state or self._create_instance_state(instance))
-        return instance
-
-    def setup_instance(self, instance, state=None):
-        setattr(instance, self.STATE_ATTR, 
-                    state or self._create_instance_state(instance))
-    
-    def teardown_instance(self, instance):
-        delattr(instance, self.STATE_ATTR)
-        
-    def _new_state_if_none(self, instance):
-        """Install a default InstanceState if none is present.
-
-        A private convenience method used by the __init__ decorator.
-        
-        """
-        if hasattr(instance, self.STATE_ATTR):
-            return False
-        elif self.class_ is not instance.__class__ and \
-                self.is_mapped:
-            # this will create a new ClassManager for the
-            # subclass, without a mapper.  This is likely a
-            # user error situation but allow the object
-            # to be constructed, so that it is usable
-            # in a non-ORM context at least.
-            return self._subclass_manager(instance.__class__).\
-                        _new_state_if_none(instance)
-        else:
-            state = self._create_instance_state(instance)
-            setattr(instance, self.STATE_ATTR, state)
-            return state
-    
-    def state_getter(self):
-        """Return a (instance) -> InstanceState callable.
-
-        "state getter" callables should raise either KeyError or
-        AttributeError if no InstanceState could be found for the
-        instance.
-        """
-
-        return attrgetter(self.STATE_ATTR)
-    
-    def dict_getter(self):
-        return attrgetter('__dict__')
-        
-    def has_state(self, instance):
-        return hasattr(instance, self.STATE_ATTR)
-        
-    def has_parent(self, state, key, optimistic=False):
-        """TODO"""
-        return self.get_impl(key).hasparent(state, optimistic=optimistic)
-
-    def __nonzero__(self):
-        """All ClassManagers are non-zero regardless of attribute state."""
-        return True
-
-    def __repr__(self):
-        return '<%s of %r at %x>' % (
-            self.__class__.__name__, self.class_, id(self))
-
-class _ClassInstrumentationAdapter(ClassManager):
-    """Adapts a user-defined InstrumentationManager to a ClassManager."""
-
-    def __init__(self, class_, override, **kw):
-        self._adapted = override
-        self._get_state = self._adapted.state_getter(class_)
-        self._get_dict = self._adapted.dict_getter(class_)
-        
-        ClassManager.__init__(self, class_, **kw)
-
-    def manage(self):
-        self._adapted.manage(self.class_, self)
-
-    def dispose(self):
-        self._adapted.dispose(self.class_)
-
-    def manager_getter(self):
-        return self._adapted.manager_getter(self.class_)
-
-    def instrument_attribute(self, key, inst, propagated=False):
-        ClassManager.instrument_attribute(self, key, inst, propagated)
-        if not propagated:
-            self._adapted.instrument_attribute(self.class_, key, inst)
-
-    def post_configure_attribute(self, key):
-        self._adapted.post_configure_attribute(self.class_, key, self[key])
-
-    def install_descriptor(self, key, inst):
-        self._adapted.install_descriptor(self.class_, key, inst)
-
-    def uninstall_descriptor(self, key):
-        self._adapted.uninstall_descriptor(self.class_, key)
-
-    def install_member(self, key, implementation):
-        self._adapted.install_member(self.class_, key, implementation)
-
-    def uninstall_member(self, key):
-        self._adapted.uninstall_member(self.class_, key)
-
-    def instrument_collection_class(self, key, collection_class):
-        return self._adapted.instrument_collection_class(
-            self.class_, key, collection_class)
-
-    def initialize_collection(self, key, state, factory):
-        delegate = getattr(self._adapted, 'initialize_collection', None)
-        if delegate:
-            return delegate(key, state, factory)
-        else:
-            return ClassManager.initialize_collection(self, key, 
-                                                        state, factory)
-
-    def new_instance(self, state=None):
-        instance = self.class_.__new__(self.class_)
-        self.setup_instance(instance, state)
-        return instance
-
-    def _new_state_if_none(self, instance):
-        """Install a default InstanceState if none is present.
-
-        A private convenience method used by the __init__ decorator.
-        """
-        if self.has_state(instance):
-            return False
-        else:
-            return self.setup_instance(instance)
-
-    def setup_instance(self, instance, state=None):
-        self._adapted.initialize_instance_dict(self.class_, instance)
-        
-        if state is None:
-            state = self._create_instance_state(instance)
-            
-        # the given instance is assumed to have no state
-        self._adapted.install_state(self.class_, instance, state)
-        return state
-
-    def teardown_instance(self, instance):
-        self._adapted.remove_state(self.class_, instance)
-
-    def has_state(self, instance):
-        try:
-            state = self._get_state(instance)
-        except exc.NO_STATE:
-            return False
-        else:
-            return True
-            
-    def state_getter(self):
-        return self._get_state
-
-    def dict_getter(self):
-        return self._get_dict
-
 class History(tuple):
     """A 3-tuple of added, unchanged and deleted values,
     representing the changes which have occured on an instrumented
@@ -1446,22 +1029,6 @@ def has_parent(cls, obj, key, optimistic=False):
     state = instance_state(obj)
     return manager.has_parent(state, key, optimistic)
 
-def register_class(class_, **kw):
-    """Register class instrumentation.
-    
-    Returns the existing or newly created class manager.
-    """
-
-    manager = manager_of_class(class_)
-    if manager is None:
-        manager = _create_manager_for_cls(class_, **kw)
-    return manager
-    
-def unregister_class(class_):
-    """Unregister class instrumentation."""
-    
-    instrumentation_registry.unregister(class_)
-
 def register_attribute(class_, key, **kw):
     proxy_property = kw.pop('proxy_property', None)
     
@@ -1486,21 +1053,24 @@ def register_attribute_impl(class_, key,
     else:
         typecallable = kw.pop('typecallable', None)
 
+    dispatch = manager[key].dispatch
+    
     if impl_class:
-        impl = impl_class(class_, key, typecallable, **kw)
+        impl = impl_class(class_, key, typecallable, dispatch, **kw)
     elif uselist:
-        impl = CollectionAttributeImpl(class_, key, callable_,
+        impl = CollectionAttributeImpl(class_, key, callable_, dispatch,
                                        typecallable=typecallable, **kw)
     elif useobject:
-        impl = ScalarObjectAttributeImpl(class_, key, callable_, **kw)
+        impl = ScalarObjectAttributeImpl(class_, key, callable_,
+                                        dispatch,**kw)
     elif mutable_scalars:
-        impl = MutableScalarAttributeImpl(class_, key, callable_,
+        impl = MutableScalarAttributeImpl(class_, key, callable_, dispatch,
                                           class_manager=manager, **kw)
     else:
-        impl = ScalarAttributeImpl(class_, key, callable_, **kw)
+        impl = ScalarAttributeImpl(class_, key, callable_, dispatch, **kw)
 
     manager[key].impl = impl
-    
+
     manager.post_configure_attribute(key)
 
     
@@ -1512,7 +1082,7 @@ def register_descriptor(class_, key, proxy_property=None, comparator=None,
         proxy_type = proxied_attribute_factory(proxy_property)
         descriptor = proxy_type(key, proxy_property, comparator, parententity)
     else:
-        descriptor = InstrumentedAttribute(key, comparator=comparator,
+        descriptor = InstrumentedAttribute(class_, key, comparator=comparator,
                                             parententity=parententity)
     
     descriptor.__doc__ = doc
@@ -1608,212 +1178,3 @@ def del_attribute(instance, key):
     state, dict_ = instance_state(instance), instance_dict(instance)
     state.get_impl(key).delete(state, dict_)
 
-def is_instrumented(instance, key):
-    """Return True if the given attribute on the given instance is
-    instrumented by the attributes package.
-    
-    This function may be used regardless of instrumentation
-    applied directly to the class, i.e. no descriptors are required.
-    
-    """
-    return manager_of_class(instance.__class__).\
-                        is_instrumented(key, search=True)
-
-class InstrumentationRegistry(object):
-    """Private instrumentation registration singleton.
-    
-    All classes are routed through this registry 
-    when first instrumented, however the InstrumentationRegistry
-    is not actually needed unless custom ClassManagers are in use.
-    
-    """
-
-    _manager_finders = weakref.WeakKeyDictionary()
-    _state_finders = util.WeakIdentityMapping()
-    _dict_finders = util.WeakIdentityMapping()
-    _extended = False
-
-    def create_manager_for_cls(self, class_, **kw):
-        assert class_ is not None
-        assert manager_of_class(class_) is None
-
-        for finder in instrumentation_finders:
-            factory = finder(class_)
-            if factory is not None:
-                break
-        else:
-            factory = ClassManager
-
-        existing_factories = self._collect_management_factories_for(class_).\
-                                difference([factory])
-        if existing_factories:
-            raise TypeError(
-                "multiple instrumentation implementations specified "
-                "in %s inheritance hierarchy: %r" % (
-                    class_.__name__, list(existing_factories)))
-
-        manager = factory(class_)
-        if not isinstance(manager, ClassManager):
-            manager = _ClassInstrumentationAdapter(class_, manager)
-            
-        if factory != ClassManager and not self._extended:
-            # somebody invoked a custom ClassManager.
-            # reinstall global "getter" functions with the more 
-            # expensive ones.
-            self._extended = True
-            _install_lookup_strategy(self)
-        
-        manager._configure_create_arguments(**kw)
-
-        manager.factory = factory
-        self._manager_finders[class_] = manager.manager_getter()
-        self._state_finders[class_] = manager.state_getter()
-        self._dict_finders[class_] = manager.dict_getter()
-        return manager
-
-    def _collect_management_factories_for(self, cls):
-        """Return a collection of factories in play or specified for a
-        hierarchy.
-
-        Traverses the entire inheritance graph of a cls and returns a
-        collection of instrumentation factories for those classes. Factories
-        are extracted from active ClassManagers, if available, otherwise
-        instrumentation_finders is consulted.
-
-        """
-        hierarchy = util.class_hierarchy(cls)
-        factories = set()
-        for member in hierarchy:
-            manager = manager_of_class(member)
-            if manager is not None:
-                factories.add(manager.factory)
-            else:
-                for finder in instrumentation_finders:
-                    factory = finder(member)
-                    if factory is not None:
-                        break
-                else:
-                    factory = None
-                factories.add(factory)
-        factories.discard(None)
-        return factories
-
-    def manager_of_class(self, cls):
-        # this is only called when alternate instrumentation 
-        # has been established
-        if cls is None:
-            return None
-        try:
-            finder = self._manager_finders[cls]
-        except KeyError:
-            return None
-        else:
-            return finder(cls)
-
-    def state_of(self, instance):
-        # this is only called when alternate instrumentation 
-        # has been established
-        if instance is None:
-            raise AttributeError("None has no persistent state.")
-        try:
-            return self._state_finders[instance.__class__](instance)
-        except KeyError:
-            raise AttributeError("%r is not instrumented" %
-                                    instance.__class__)
-
-    def dict_of(self, instance):
-        # this is only called when alternate instrumentation 
-        # has been established
-        if instance is None:
-            raise AttributeError("None has no persistent state.")
-        try:
-            return self._dict_finders[instance.__class__](instance)
-        except KeyError:
-            raise AttributeError("%r is not instrumented" %
-                                    instance.__class__)
-        
-    def unregister(self, class_):
-        if class_ in self._manager_finders:
-            manager = self.manager_of_class(class_)
-            manager.unregister()
-            manager.dispose()
-            del self._manager_finders[class_]
-            del self._state_finders[class_]
-            del self._dict_finders[class_]
-        if ClassManager.MANAGER_ATTR in class_.__dict__:
-            delattr(class_, ClassManager.MANAGER_ATTR)
-        
-instrumentation_registry = InstrumentationRegistry()
-
-def _install_lookup_strategy(implementation):
-    """Replace global class/object management functions
-    with either faster or more comprehensive implementations,
-    based on whether or not extended class instrumentation
-    has been detected.
-    
-    This function is called only by InstrumentationRegistry()
-    and unit tests specific to this behavior.
-    
-    """
-    global instance_state, instance_dict, manager_of_class
-    if implementation is util.symbol('native'):
-        instance_state = attrgetter(ClassManager.STATE_ATTR)
-        instance_dict = attrgetter("__dict__")
-        def manager_of_class(cls):
-            return cls.__dict__.get(ClassManager.MANAGER_ATTR, None)
-    else:
-        instance_state = instrumentation_registry.state_of
-        instance_dict = instrumentation_registry.dict_of
-        manager_of_class = instrumentation_registry.manager_of_class
-        
-_create_manager_for_cls = instrumentation_registry.create_manager_for_cls
-
-# Install default "lookup" strategies.  These are basically
-# very fast attrgetters for key attributes.
-# When a custom ClassManager is installed, more expensive per-class
-# strategies are copied over these.
-_install_lookup_strategy(util.symbol('native'))
-
-def find_native_user_instrumentation_hook(cls):
-    """Find user-specified instrumentation management for a class."""
-    return getattr(cls, INSTRUMENTATION_MANAGER, None)
-instrumentation_finders.append(find_native_user_instrumentation_hook)
-
-def _generate_init(class_, class_manager):
-    """Build an __init__ decorator that triggers ClassManager events."""
-
-    # TODO: we should use the ClassManager's notion of the 
-    # original '__init__' method, once ClassManager is fixed
-    # to always reference that.
-    original__init__ = class_.__init__
-    assert original__init__
-
-    # Go through some effort here and don't change the user's __init__
-    # calling signature.
-    # FIXME: need to juggle local names to avoid constructor argument
-    # clashes.
-    func_body = """\
-def __init__(%(apply_pos)s):
-    new_state = class_manager._new_state_if_none(%(self_arg)s)
-    if new_state:
-        return new_state.initialize_instance(%(apply_kw)s)
-    else:
-        return original__init__(%(apply_kw)s)
-"""
-    func_vars = util.format_argspec_init(original__init__, grouped=False)
-    func_text = func_body % func_vars
-
-    # Py3K
-    #func_defaults = getattr(original__init__, '__defaults__', None)
-    # Py2K
-    func = getattr(original__init__, 'im_func', original__init__)
-    func_defaults = getattr(func, 'func_defaults', None)
-    # end Py2K
-
-    env = locals().copy()
-    exec func_text in env
-    __init__ = env['__init__']
-    __init__.__doc__ = original__init__.__doc__
-    if func_defaults:
-        __init__.func_defaults = func_defaults
-    return __init__